US1720413A - Electrically-operated circuit interrupter - Google Patents

Description

July 9, 192%.. T. T, GREENWOOD ELF'C' 'R CALI-Y OPERATED CIRCUIT INTERRUPTER Original Filed Oct. 30, 1926 has .luly- 9,I '1929.-

UNITED STATES PATENT OFFICE.

.nm 'r. emuwoon, 01? mar TEMPLETON, MASSACHUSETTS, assrcnoa we conm'r nncrmcan Immmc'runmc coaromrron, or nos'rou, massacnusmrs, a CORPORATION or xassacnusn'r'rs.

nLnc'rmcamY-orumrnn cincurr mrEanuPrnn- Application mm October so, 1926, semi 110. 145,327. l lenewedjlq'ovembcr 17, 1928.

This invention relates to electric circuit interrupters of the vacuum type wherein the circuit is broken in a highly evacuated container and .between separable contact members from which the occluded gases have been removed.

An object of this invention is to provide an 2 improved arrangement of the vacuum switch and its accessory apparatus to reduce the space required for-the installation of the switch and also to provide ahigh factor of insulation between the .switch and adjacent obects.

J A further object is to provide an improved mechanism for opening and closing 'the switch, I

Another object of the invention is to provide a vacuum switch so arranged v that, it

can carry continuously a heavy current with-'- out danger of damage to the evacuated container.

A yet further object is generally to improve the construction and operation of circuitinterrupters. p V

Fig. 1 isa sectional elevation taken through a circuit interrupter embodying the invention.'

the manner of coolingthe open top of the receptacle is normally closedby a removable cover'12 which cover comprises a switch frame that supports the esto the surrounding atmosphere through the 5 sential elements of the interrupter:

The interrupter is provided with a pair of insulated terminals 14 which arezcarried by and extend through-the cover 12 and termi- 'nate beneath the surface of the oil in the casing.

The vacuum switch forming apart of this invention is connected electrically with" and is supported mechanically by said terminals and said terminals constitute .the sole sup- Fig. 2 is a sectional detail through one of the contact members of the vacuum switch as glass. Said containeris provided with a neck 18 at'the bottom thereof and upwardly- J extended divergent ne cks 20 at the topr'thereof. Metal caps 22 are welded to said necks 20 and form closures therefor. ,The vacuum switch is provided with relatively large coii- 6o tact members which include studs 24. Said studs are integral with said caps 22 and are extended through said necks 20 into the body of the-container. The studs at the lower ends are terminated inopposed and spaced conclamp said straps in firm mechanical and electrical contact with said'cap's. Said-straps are substantially of U-shape and the upper legs of said straps are clamped by nuts 34 to the lower ends of the terminals 14. This arrangement serves to rigidly connect the vacuum switch mechanically as well as electrically with said terminals. The'circuit interrupter here shown is adapted to carry a relatively large amount of current.' To this end, the studs 24 are made hollow or are .proso vided with internal passages 36 as shown most clearly'in'Fig. 2 and said passages are I open at their upper ends only and are in free communication with the body of "oil contained in the enclosing casing. 0001 oil is 5 adapted to flowv into said passages and hot oil is adapted to flow out of said passages by thermal circulation, thereby to keep the studs cool and prevent damage to the container 16.

The caps 22 and the straps 30 are also ex 0 posed to the cool body of insulating fluid in which they are immersed andthus are maintained cool. The heat absorbed by thebody of hot insulating fluid is ultimately given up heat-conducting walls of the oil receptacle 10. The contact members 26- are adapted to be therebetween and is adapted to held in the aforesaid .position to maintain the circuit closed. The brid ing member is adaptedto be moved 'downwar, y to interrupt the circuit. 5

' The switch is electricallyopened and closed. The switch operatin mechanism'com rises X a metal tube 40 whic is sealed at its ower end and which has its u perand open end welded to the neck 18 o the container; A similar metal tube 42 is welded to the tube 40 at right angles therewith and intermediate its length. A second metal tube 44 is welded in a similar manner to said tube 42 and in a line with said first tube 42. The joints 'between the tubes 42 and 44 is such as to provide avacuum-sealed connection therebetween. solenoid 46' constituting the closing solenold magnetic core or plunger 50 is received within said tubes 42 and 44 andis reciprocable therein under the influence of said solenoids.

Saidplunger is adapted to be moved toward the right to open the switch and toward the left to close the switch. Said plunger is adapted to reciprocate a switch-operating member or piston 52. Said iston is disposed to slide freely within the tu and is connected with said bridging member 38 by means of a rod 54 of insulatin material as glass. Said piston is provide with a verticallyselongated slot 56 therein in which said plunger 50 is freely movable. k The lower wall of said slot is given a V-shape asindicated at 58, whereby to form a cam face that is adapted to be engaged by the plunger to effect the opening of the switch. The plunger 50 is provided with a notch 60 in its lower portion. The left hand edge of said notch is inclined as'indic'ated at 62 thereby to provide a cam face which is adapted to enga e the correspondingcam face of the projection 58 so that the movement of the plunger and the rod serves to depress the giiston 52 and thereby to open the switch. aid plunger is provided with a flat lower face 64 adapted to be engaged by the top or apex of the projection 58 thereby to hold the switch in open position until it is closed. A compression spring 66 is disposed under the piston and serves to urge it constantly toward switch-closed position. 7 The movement of the plunger in a direction to open'the switch serves to operate the piston against the action of said spring. The movement of the plunger towards switchclosedpositiom'however, serves to release the plunger for movement toward switch closed position by said spring. The terminals a and b of the opening and closing solenoids respec: tively may be brought out of the casing through insulating bushings 68 in the cover 12.

By the arrangement here shown, 'the vacuum switch is supported entirely by the interrupter terminals 14. By immersing the entire vacuum switch and its operatin mech-' anism in a body of insulating liquid, a equate insulation is provided between the terminals of the vacuum switch andthe mechanism so that the dimensions of the vacuum switch can be made relatively small and the apparatus 'sulating liquid, ad uate insulation is can thereby be quite compact. Also by immersing the vacuum switch in the body of in rovided between the switch and adjacent objects and the s ace required for the installation of the switc is relatively moderate.

The container 16 is adapted to be evacuated to as high a degree as is practicable. All of the parts disposed within said container or in communication with the interior therein are adapted to have the occluded gases removed therefrom and especially from the contact members 26. Under these conditions, a relatively large amount of energy can be interrupted rapidly for a small opening movement of the bridging member 38.

My concurrently filed application, Serial No. 145,326, also "discloses an oil-immersed vacuum switch wherein the vacuum switch casing is carried b insulating bushings. My concurrently file application, Serial No. 145,328, also discloses a switch wherein the contacts. are separated in ahigh vacuum. The concurrently filed application of George A. Burnham, Serial No. 145,321, also discloses an electrically-operated and oil-immersed vacuum switch. All of these applications are assigned to the assignee of this application.

I claim: 4

1. An electric switch having an oil containing casing, a pair of bushings rigidly carried by said casing and depending into the oil in said casing and having a pair of spaced contact members at and rigid with the lower ends of said bushings, an evacuated container surrounding andenclosing said contact members and carried by both of said bushings, and a movable bridging member disposed within said evacuated container in cooperative rela-.

tion with said contact members.

2. An electric switch havmg an oil containing casing provided with a cover, a pair of bushings attached rigidly to said cover and extending upwardly thereabove and also de-' pending downwardly into the oil in said oil receptacle, an evacuated container disposed between and beneath the lower'ends of said llt bushings in the oil in said casing and having members connected rigidly with said terminals and extended downwardly within said evacuated container approximately in the line of said bushings, and a movable bridging member disposed within said evacuated container and cooperating with said contact members, said bushings providing the sole support for said evacuated container,

3. An electric switch having an oil containing casing provided with a cover, apair of bushings attached rigidly to said cover and extending upwardly thereabove and also de- 30 the body of said container in cooperative relapendingdowhwardly into the oil in said oil receptacle, an evacuated container di osed between and'beneath the lower ends said bushings in the oil in said casing and having a pair of exposed terminals disposed be- .jneath the lower ends of said bushin s, attaching means rigidly connecting eac of said terminals electrically and also mechanically i with an adjacent bushin stationary contact members connected rigi y with said terminals and extended downwardly within said evacuated container approximately in the line of said bushings, and a movable bridging member disposed within said evacuated container and cooperating with said contact members, and operating mechanism for said bridging member carried by said evacuated container below said terminals and bridging member, said bushings constituting the-sole supporti means for said evacuated container an operating mechanism.

41A circuit interrupter comprising an evacuatedcontainer comprising a y anda pair of spaced necks upstandin thereabove, ex d terminals carried y said necks, stationary contact members connected electrically and rigidly mechanically with said necks and extended downwardly within said necks into the body of said container, a movable bridging member disposed within tion with said contact members and operat- 4 ing mechanism carried bysaidcontainer ata the bottom thereof and beneath said contact.

members and bridging member and having. an opzrative connection with said bridging mem r. r I

5. A circuitinterrupter including an evacuated container, contact members disposed within said container, at least one of which contact members is fixed to' the wall of said container and extends outwardly therethrough, said fixed contact member having a passage thereinjwhich is open only outside said container, and means to maintain a .circulatory body'ofinsulating fluid'in said pasg A circuit interrupter including an evacuated container, contact members disposed within; said container, at least one of which contact members is fixed to the wall of said I containerv and extends outwardly therefi 7. In a circ 't gtion of an evacuated container; and movable contact members contained therein, said fixed contact members being extended -.-through, said' fixed contact member having a passage therein'which is open ,only' outside said container; and means to cool said contact member including means to maintain a cirolflatorybody of coolfinaulating fluid.

insaidpassage- 1 interrupter, the" combinathrough'the wall of said container, an ope-- atingnmechanism for the" movable contawt mom 7 rincluding a tube connected with said container at one end and sealed at the other end, a switch oarating member re'ciprocable' through the wall of said container, an operating mechanism for the movable contact member including a tube connected with said container at one end and sealed at the other end, a switch-o rating member reciprocable within said tu and having a connection with said movable contact member, said tube having opposed branch-tubes which are sealed attheir outer ends, closing and opening solenoids surrounding said branch-tubes and a plunger common to both branc '-tubes and having an operative connection with said switch operating member whereby'to reciprocate it, and means to bias said switch operating member for movement in one directlon.

9. In a circuit interrupter, the combination of an evacuated container, fixed and movable contact members therein, said fixed contact member being extended through the 'wall of said container, operating'mechanism for the movable contact member including a tube connected with said container at one end and led at the-other end, a' switch operating member reciprocable withinsaid tube andhaving a connection with said mov able contact member, said. tube having op posed branch-tubeswhich'are sealed at their outer ends and are .in free communication with said first tube at their inner ends, closing and o ning solenoids surrounding said branch-tn a plan r common to bothbranch tubes and having an operative connection with said switch operating member whereby to reciprocate it, and means to bias said switch operating member for. movement toward switch-c osed position; 10,-In a circuit'interrupter, the combination, of an evacuated container, fixed and movable contact-members therein, said fixed contact members being extendedthrough the wall in said container, operating mechanism for the movable contact member "including a tube connected with said container at one end and sealed at the other end, a switch. operatin member reciprocable within said f tube an having a connection with said movable contact member, said tube having opposed branch tubes which are sealed at their outer ends and are in free communication with said first tube at their inner ends, closing and opening solenoids surrounding said branch-tubes, a plunger common to both branch-tubes -and having an operative connection with said switch connecting member whereby to reciprocate it, and means to bias said switch operating member for movement 'towa'rd sgitch-closed position, said plunger having means cooperating with said switch operating member to restrain it against action of its biasing means.

11. An electric switch having an oil containing casing, a pair of bushings rigidly carried by sald casing and depending into the oil in 'said casing and having a pair of spaced contact members at the lower ends of said bushings, an evacuated container surrounding and enclosing said contact memhers and carried by both of said bushings,

and a movable bridging member disposed 50 within said evacuated container in cooperative relation with said contact members.

12. A circuit interrupter having a PallOf fixed-insulated terminals, and an evacuated container having stationary and movable 25 contact members, the stationary contact members having terminal portions external of said evacuated container, said container having a mechanical connection with said insulated terminals and the exposed terml- 30 nal portions and its stationary contact mem- TALMA T. GREENWOOD.

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